Display device including resilient mounting means

ABSTRACT

A display device comprises an envelope having a stem including leads therethrough. Mounted on the leads within the envelope is a rigid substrate having a plurality of light sources thereon. To prevent movement of the substrate relative to the envelope, leaf springs are provided rigidly affixed to the substrate and in spring-flexed engagement with the inside wall of the envelope.

United States Patent [72] Inventor NormanLeeLindburg Berkeley Heights, NJ. 21 AppLNo. 824,057

[22] Filed May 13, 1969 [45] Patented July 20, 1971 10/1936 Hirmann 2,094,654 10/1937 Hirmann 2,113,952

[73] Assignce RCACorporation 4/1938 Stembergmm 2,880,350 3/1959 Klepp............ 3,416,020 12/1968 Carley..........................

Primary Examiner-John Kominski Attorney-Glenn H. Bruestle [54] DISPLAY DEVICE INCLUDING RESILIENT ABSTRACT: A display device comprises an envelope having a stem including leads therethrough. Mountedon'the leads /1095, within the envelope is a rigid substrate havin MOUNTING MEANS 9Claims,6Dnwing Figs.

g a plurality of of the substrate springs are provided rigidly afspring-flexed engagement with 313/50, 313/269, 313/316, 313/288 noi 61/66 313 1095,

[51] lnt.Cl............... [50] 278 the inside wall ofthe envelope.

PATENTED JUL20197| INVEIV TOR Norman Lee Lindburg Arron" DISPLAY DEVICE INCLUDING RESILIENT MOUNTING MEANS BACKGROUND OF THE INVENTION This invention relates to display devices of the type comprising a rigid substrate having a plurality of light sources mounted thereon, and an envelope in which the substrate is mounted.

In display devices of the type described, the light sources, e.g., electrical resistance filaments, are often very delicate and subject to damage upon vibration of the substrate upon which they are mounted. In one prior art device, the substrate is wedged in place between one end of the envelope and combination support and terminal leads passing through the opposite end of the envelope. Although this arrangement is generally satisfactory, upon excessive mechanical shocking of the device, the leads can become bent, thereby reducing the substrate wedging pressure and giving rise to possible excessive vibration of the substrate.

SUMMARY OF THE INVENTION A display device is provided comprising an envelope, a substrate within the envelope, and a resilient member affixed to the substrate and in wedged engagement with the inside wall of the envelope.

DESCRIPTION OF THE DRAWING FIG. 1 is a front elevation, partly broken away, of a novel display device according to the present invention;

FIG. 2 is a partial section of the device shown in FIG. I taken along the line 2-2 thereof;

FIG. 3 is a section taken along the line 33 of FIG. 1; FIG. 4 is a view, in perspective, showing various subassemblies which are assembled together to provide the device shown in FIG. I; and

FIGS. 5 and 6 are views in perspective of substrates including different modifications of the resilient means for mounting the substrates within the envelope.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION With reference to FIGS. I and 2, a display device 10 is shown which comprises an elongated transparent glass envelope l2 closed at its upper and lower ends 14 and 16, respectively, and having a circular cross section. The lower end 16 of the envelope 12 includes a stem 18 having a plurality, e.g., 9, through leads 20. The upper end 14 of the envelope is dome shaped.

Mounted on the leads 20 within the envelope 12 is a thin, flat substrate 24, of, for example, an alumina ceramic having a dark and dull surface to minimize light reflection. Extending through the substrate 24, in bonded relation therewith, are a plurality of support elements'or posts 26. Mounted between pairs of posts 26, on the "front side, as viewed in FIG. 1, of the substrate 24, are a plurality of light sources 29. In this embodiment the light sources comprise rectilinear electrical resistance filaments 30, 31, 32, 33, 34, 35 and 36, each comprising an elongated coil of refractory wire, e.g., an alloy comprising 97 percent tungsten and 3 percent rhenium, by weight.

By selectively energizing various ones of the filaments, that is, by applying a voltage between the pairs of posts 26 between which the selected filaments are mounted, various luminous images or symbols, numerals, in the instant embodiment, are obtained. For example, an image of the numeral 2 is obtained by lighting the filaments 30, 31, 36, 34, and 33, each filament providing an elongated element or segment of the composite image.

Display devices of the type to the extent so far described are known. See, for example, US. Pat. No. 3,416,020, issued to .l. A. Carley on Dec. 10, I968.

To restrain movement of the substrate 24 within the envelope 12, a frame 40, formed from a thin metal sheet, is provided mounted on the substrate 24. As shown in FIG. 4, the frame 40 has a generally U-shape, including two dependent legs 42 and a leg connecting member 46. The frame 40, as shown in FIGS. 1 and 3, is mounted astride the edges of the substrate 24, the two dependent legs 42 being disposed along the two longitudinally extending edges 50 (FIG. 4) of the substrate, and the leg connecting member 46 being disposed along the upper substrate edge 54. To maintain the frame 40 in position on the substrate 24, the leg connecting member 46 has dependent sides 56 which engage opposite faces 60 and 62 of the substrate 24, and the frame legs 42 include dependent straps 64 which likewise engage the substrate faces 60 and 62. Also, the ends 66 of the frame legs 42 are inwardly bent to extend at least partially around the rounded lower corners of the substrate 24.

Each frame leg 42 includes an enlarged portion or flange 70 which is perpendicular to a plane including both legs 42 of the U-shaped frame, hence perpendicular to the faces 60 and 62 of the substrate 24 when the frame 40 is mounted thereon. As shown in FIG. 3, the outer edges 72 of each of the flanges 70 engage the inside wall of the envelope at points A and B. The transverse width or extent of the flanges 70, prior to the mounting of the frame 40 within the envelope 12, is greater than the length of the chords between the points A and B on the circular inner envelope wall. Thus, within the envelope I2, the flanges 70 are inwardly flexed by contact with the envelope wall, as shown in FIG. 3.

The thin metal flanges 70 are resilient, thus serving as compressively stressed or flexed leaf springs holding the frame 40 tightly clamped about the substrate 24, and maintaining the substrate 26 in fixed longitudinal and lateral relationship with the envelope.

An advantage of this construction is that a fixed relationship between the envelope and the substrate is provided which is substantially independent of the mounting of the substrate on the stem leads 20. This reduces the problem, hereinbefore referred to, of the possibility of a loose mounting of the substrate within the envelope upon mechanical shocking of the device to an extent sufficient to bend the stem leads. A further advantage of this construction, in comparison with the prior art construction referred to, is that a proper mounting of the substrate within the envelope is less dependent upon the tolerance to which the leads are formed, thus simplifying fabrication of the device.

As shown in FIG. 4, the upper edge 74 of the frame flanges 70 taper outwardly in a downwardly direction. This facilitates assembly of the device, as now described.

In the assembly of the device, the substrate 24, having the various light sources 29 mounted thereon, is mounted on the stem 18 by welding the various leads 20 to various ones of the filament support posts 26. Thereafter (reference being made to FIG. 4), the frame 40 is slid around the edges of the substrate 24. While the frame 40 can be designed to be self-supporting about the substrate, by spring pressure of the frame legs 42 against the substrate, it is found more convenient, with respect to the ease of initial mounting of the frame on the substrate, to design the frame so that the legs slightly diverge, the distance between the legs near the leg connecting member 46 being about equal to the width of the substrate 24. Thus, to maintain the frame on the substrate, it is necessary to squeeze the frame legs 42 against the substrate by, most simply, the fingers of the assembler, or by an appropriate jig, not shown. Thereafier, the substrate-stem-frame assembly, known as a mount, is inserted through the lower open end of a bulb 82. As shown, the bulb 80 comprises a tubular glass member open at one end 80, the other end 84 having a dome shape, and an elongated, hollow tubulation 86 opening into the inside of the bulb through the dome end 84.

During the insertion of the mount into the bulb, the upper edges 74 of the frame flanges 70 engage the edge of the bulb wall owing to the large transverse extent of the flanges 70 relative to the inner dimensions of the bulb, as previously described. The taper of the edges 74 of the flanges 70 provide a camming action, in connection with the bulb wall edge, to gradually inwardly flex the flanges to facilitate the insertion operation.

The mount is inserted just far enough to provide the proper longitudinal spaced relation between the bulb lower end 80 and the stem 18 to obtain proper eventual joining of the two in a glass-to-glass seal. Preferably, the upper end of the substrate 24 does not engage the inside wall of the dome end 84 of the bulb. An advantage of this is that, upon mechanical shocking of the device, banging of the rigid substrate against the rigid wall of the envelope is avoided, thus avoiding the possibility of damage to either from such hard surface to hard surface contact. Additionally, transmittal of mechanical shock to the substrate from the envelope is reduced owing to the resilient leaf spring mounting of the substrate within the envelope, the substrate nowhere being in direct engagement with the envelope wall.

The spring flexure of the frame flanges 70 maintains the bulb and mount in fixed relationship. The unitary assembly is thus relatively immune to damage upon further handling of the assembly prior to and during the sealing operation. A further advantage of the described device is that because the frame 40 is held in place within the envelope solely by being compressively wedged between the envelope wall and the substrate 24, the substrate need have no special shape or features to allow attachment of the frame 40 thereto, the frame 40, as described, engaging substantially only peripheral portions of the substrate. The flat, rectangular substrate 24, of a ceramic material, in the instant embodiment, is relatively simple to fabricate, and is relatively inexpensive owing to its simplicity. Somewhat more complex substrates, such as the ones shown in FIGS. 5 and 6, for example, described hereinafter, are more expensive owing to the greater loss of product due to defects arising specifically from the greater complexity of the substrates.

After the mount is inserted into the bulb 82, the lower end 80 of the bulb 82 is sealed to the stem 18, according to known techniques, the device is exhausted and/or back filled with suitable gases through the tubulation 86, and the tubulation tipped off.

In the embodiment shown in FIG. 5, a substrate 90 is provided including two longitudinally extending slots (not visible) adjacent to the longitudinally extending sides 50 of the substrate. Two flanges 92 are disposed through the slots in forcefit relation therewith. The width of the flanges 92 are of such size to provide a compressively stressed engagement of the flanges with the inside wall of the envelope when the substrate 90 is inserted into the envelope.

In the embodiment shown in FIG. 6, a substrate 94 is provided having a pair of spaced grooves 96 in each of the two longitudinally extending edges 50 of the substrate. Disposed along each edge 50 is a narrow leaf spring or strap 98, the ends of the straps being wedged in the grooves 96, and the straps being maintained in compressively stressed condition by virtue of the distance between the grooves on each side 50 of the substrate being less than the lengths of the straps. The maximum distance between the two straps 98, from crown to crown of the arched straps, is slightly greater than the diameter of the envelope, whereby the straps 98 are further compressively stressed upon being forcibly inserted into the envelope.

By way of example, the substrate 24 in the embodiment shown in FIG. 1 is 800 mils long by 700 mils wide, and has a thickness of 75 mils. The bulb 82 has a nominal inner diameter of 740 mils, with a tolerance, in commercially available bulbs, in the order of :20 mils. The frame 40 is formed from 5 mils thick aluminum clad steel, and the width of the flanges 70, i.e., the unflexed transverse extent thereof, is 255 mils.

In the embodiment shown in FIG. 5, the flanges 92 are disposed at a distance of 280 mils from the longitudinal axis of the substrate 90, which has the same dimensions as the substrate 26, and each flange 92 has a width of 470 mils, a length of 505 mils, and a thickness of 5 mils. The slots through the substrate have a width of 20 mils and a length of 500 mils.

In the embodiment shown in FIG. 6, the straps 98 have'a length of 500 mils, a width of mils, and a thickness of 5 mils. The distance between the grooves 96 on each side of the substrate is 530 mils.

What I claim is:

l. A display device comprising:

an envelope;

a rigid substrate within said envelope;

a plurality of light sources mounted on a face of said substrate, and terminal means engaged with each of said sources allowing individual operation of said sources; and

resilient means for restricting movement of said substrate relative to said envelope, said means comprising a U- shaped member having a pair of legs mounted to extend along oppositely disposed sides of said substrate, one of said legs including a metal leaf spring in compressively stressed engagement with the inside wall of said envelope.

2. A display device as in claim 1 wherein said resilient means maintains said substrate out of direct engagement with the wall of said envelope.

3. A display device as in claim I wherein said resilient means is held in place solely by being compressively wedged between said envelope and said substrate, and said resilient means engage only nonreentrant, peripheral portions of said substrate.

4. A display device as in claim 1 wherein said substrate is relatively thin and flat, and said resilient means is mounted astride the edges of said substrate in a plane parallel to the major faces of said substrate.

5. A display device as in claim 1 wherein said substrate is relatively thin and flat, and

said resilient means comprises a sheet metal strip disposed along an edge of said substrate and having a pair of opposed tabs bent to lie adjacent opposite faces of said substrate, and each of said legs includes an enlarged planar portion extending along a longitudinal edge of said substrate, the two outer extremities of said portions being engaged with the internal wall of said envelope, said portions being flexed in a leaf spring action to urge said legs against said substrate.

6. A display device as in claim 1 wherein:

said envelope is cylindrical;

said substrate is a rectangular platelike member, opposite edges of said substrate being disposed adjacent to and extending longitudinally along the inner wall of said envelope, and

said U-shaped member is disposed along three of the four edges of said substrate with the said two legs being wedged between the envelope wall and said two longitudinally edges of said substrate.

7. A display device as in claim 1 wherein:

said envelope has a cylindrical shape including closed upper and lower ends, said lower end including a stern having a plurality of leads extending therethrough into and outwardly from said envelope;

said substrate is relatively thin and flat, and is mounted on said leads in longitudinally extending relation within said envelope;

said resilient means legs are disposed along the longitudinally extending edges of said substrate; and

each of said legs includes a leaf spring flange extending transversely of a plane including both of said legs and into compressively stressed engagement with the cylindrical sidewall of said envelope, said flanges being inwardly flexed, thereby clamping said legs rigidly against said substrate.

8. A display device as in claim 7 wherein the upper edges of said leaf springs taper outwardly and downwardly from said envelope upper end.

9. A display device as in claim 7 wherein said 'rsfiEfiT" means maintains said substrate out of direct engagement with the wall of said envelope. 

1. A display device comprising: an envelope; a rigid substrate within said envelope; a plurality of light sources mounted on a face of said substrate, and terminal means engaged with each of said sources allowing individual operation of said sources; and resilient means for restricting movement of said substrate relative to said envelope, said means comprising a U-shaped member having a pair of legs mounted to extend along oppositely disposed sides of said substrate, one of said legs including a metal leaf spring in compressively stressed engagement with the inside wall of said envelope.
 2. A display device as in claim 1 wherein said resilient means maintains said substrate out of direct engagement with the wall of said envelope.
 3. A display device as in claim 1 wherein said resilient means is held in place solely by being compressively wedged between said envelope and said substrate, and said resilient means engage only nonreentrant, peripheral portions of said substrate.
 4. A display device as in claim 1 wherein said substrate is relatively thin and flat, and said resilient means is mounted astride the edges of said substrate in a plane parallel to the major faces of said substrate.
 5. A display device as in claim 1 wherein said substrate is relatively thin and flat, and said resilient means comprises a sheet metal strip disposed along an edge of said substrate and having a pair of opposed tabs bent to lie adjacent opposite faces of said substrate, and each of said legs includes an enlarged planar portion extending along a longitudinal edge of said substrate, the two outer extremities of said portions being engaged with the internal wall of said envelope, said portions being flexed in a leaf spring action to urge said legs against said substrate.
 6. A display device as in claim 1 wherein: said envelope is cylindrical; said substrate is a rectangular platelike member, opposite edges of said substrate being disposed adjacent to and extending longitudinally along the inner wall of said envelope, and said U-shaped member is disposed along three of the four edges of said substrate with the said two legs being wedged between the envelope wall and said two longitudinally edges of said substrate.
 7. A display device as in claim 1 wherein: said envelope has a cylindrical shape including closed upper and lower ends, said lower end including a stem having a plurality of leads extending therethrough into and outwardly from said envelopE; said substrate is relatively thin and flat, and is mounted on said leads in longitudinally extending relation within said envelope; said resilient means legs are disposed along the longitudinally extending edges of said substrate; and each of said legs includes a leaf spring flange extending transversely of a plane including both of said legs and into compressively stressed engagement with the cylindrical sidewall of said envelope, said flanges being inwardly flexed, thereby clamping said legs rigidly against said substrate.
 8. A display device as in claim 7 wherein the upper edges of said leaf springs taper outwardly and downwardly from said envelope upper end.
 9. A display device as in claim 7 wherein said resilient means maintains said substrate out of direct engagement with the wall of said envelope. 